Calvin and Hobbes is my all-time favorite comic strip. It wasn't until high school that I realized the absolute genius of Bill Watterson. He peppered the conversations between Calvin and his stuffed tiger with such interesting social commentary that millions of readers of all ages found something enjoyable in his comic strips.
When I was a kid, I absolutely devoured all the collected Calvin & Hobbes comics at my library. I even convinced my parents to buy the Sunday newspaper so my sister and I can read the full-color Sunday C&H strips.
A few weeks ago I stumbled upon Gerry Canavan's blog post collecting some Calvin and Hobbes fanart depicting a grown-up Calvin.Here's a favorite and one for all the dads:
Calvin's daughter looks a little bit like a blonde Susie Derkins, the slimy girl next-door. If you remember, Calvin formed a secret anti-Susie treehouse club called G.R.O.S.S. It stood for Get Rid Of Slimy girlS.Here's another one of Calvin and Susie all grown-up.
I really like the coloring of this image, but it's a bit sappy for me. The Calvin I know wouldn't blush like that...
And there are a bunch more at Gerry Canavan's blog, some potentially even NSFW.